JP2008242685A - Failover method, cluster system, information processor, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance system reliability and user convenience by promptly taking over a process while keeping the provision of services from being stopped. <P>SOLUTION: A failover method, for use in a cluster system having a plurality of information processors capable of providing the same information service to prescribed computers connected to each other via a network, has a connection state information duplication process for causing a particular information processor being in communication with a computer to send connection state information to another information processor as the information required to reproduce the state of connection with the computer to the other information processor, and causing the other information processor to receive and store the sent connection state information, and a connection reproduction process for causing the other information processor to reproduce the state of connection with the computer according to the state of the particular information processor, and based on the stored connection state information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a failover method, and more particularly to a failover method for switching information processing apparatuses that constitute a cluster system and are connected to a client terminal.

  With the development of computers and network systems, various information services are provided via a network from server computers installed on the network. Such an information system via a network can be said to be a social infrastructure now, and high reliability is required for hardware and software supporting the information system. For this reason, in recent years, even if a failure occurs in a server, another server is configured to take over the processing. Such a function that information processing apparatuses such as a plurality of server computers mutually monitor the state and substitute processing is called a failover function. The failover function is required to be maintainable so that the processing of the server in which the failure has occurred can be taken over in the shortest possible time and the alternative processing can be resumed.

JP 2005-182781 A

  However, as described above, when performing a failover in a computer system that provides a service on the network, the service must be temporarily stopped while the server providing the service is transferred to another alternative server. There was a problem of having to. For example, in a system that provides a file sharing service, when the CIFS protocol is used for network connection, if the TCP connection is disconnected, it is necessary to reconnect by discarding the previous state. It took a certain amount of time.

  Here, in Patent Document 1, the main processor stores data in a checkpoint state in a network-connected persistent memory unit, and the backup process acquires the checkpoint state, and when the main process fails, A system for performing a function is disclosed.

  However, in the above prior art, since the data of the check point state of the main processor is once stored in the memory unit, the backup processor needs to take over the processing quickly, such as when the main processor fails. However, there is a problem that it takes time to acquire checkpoint state data, and the process restart may be temporarily stopped.

  Also, depending on the checkpoint setting, the process contents of the main processor may not be guaranteed and may be taken over by the backup processor, which may cause a problem that the reliability may be lowered.

  Furthermore, there is a problem that it is necessary to set a special checkpoint for an application that executes a process in advance, which increases the effort for creating the application and increases the processing load.

  For this reason, the present invention improves the inconveniences of the above-mentioned conventional example, and in particular, can improve the reliability of the system by taking over the processing promptly while suppressing the suspension of service provision, and the user's An object of the present invention is to provide a failover method capable of improving convenience.

Therefore, in one embodiment of the present invention,
A failover method in a cluster system comprising a plurality of information processing devices capable of providing the same information service to a predetermined computer connected via a network,
A specific information processing apparatus in communication connection with a computer transmits connection state information, which is information necessary for reproducing the connection state with the computer to another information processing apparatus, to the other information processing apparatus, and this transmission A connection state information duplication step in which another information processing apparatus receives and stores the connection state information,
A connection reproduction step in which another information processing apparatus reproduces a connection state with a computer based on the stored connection state information according to the state of the specific information processing apparatus,
It is characterized by having.

  According to the above invention, first, in a cluster system, when a specific information processing apparatus is connected to a predetermined computer and a certain information service is provided, the specific information processing apparatus is connected to indicate a connection state with the computer. The status information is transmitted to another information processing apparatus. Then, the other information processing apparatus receives and stores the transmitted connection state information. After that, when a failure occurs in the specific information processing apparatus, the other information processing apparatus uses the connection state information acquired and stored from the specific information processing apparatus to communicate with the computer. Reproduce the connection status. Thereby, the connection with the computer is switched to another information processing apparatus, and the provision of the information service is continued. Therefore, the information processing apparatus that provides the service can be switched quickly, and the service provision is suppressed from being stopped, so that the reliability of the system can be improved and the convenience of the user can be improved. be able to.

  The connection state information duplicating step transmits the connection state information to another information processing device at a timing when a predetermined transmission / reception process between the specific information processing device and the computer is normally executed. Yes. Specifically, the connection state information duplication step is characterized in that connection state information is transmitted to another information processing device at a timing at which an ACK signal is transmitted and received between the specific information processing device and the computer. In particular, it is characterized in that connection state information is transmitted to another information processing apparatus at a timing when a specific information processing apparatus transmits an ACK signal to the computer.

  As a result, a specific information processing apparatus transmits connection state information indicating a connection state with the computer to another information processing apparatus at the timing when the transmission / reception process of the computer is normally executed, for example, the transmission / reception timing of the ACK signal. To do. Therefore, since the specific information processing apparatus transmits and stores the connection state information at that time to another information processing apparatus at the timing when the transmission / reception data with the computer is guaranteed, the other information processing apparatus thereafter Even when switching to the information processing apparatus occurs, it is possible to take over the processing without data loss. As a result, the reliability of the system can be improved and the convenience of the user can be improved. Also, by using an ACK signal that is normally transmitted and received during communication as the transmission timing of connection state information, there is no need to set in advance a special checkpoint such as an application on a specific information processing apparatus side. And the processing burden on the information processing apparatus can be suppressed.

  In the connection state information duplication step, a specific information processing device transmits connection state information to a plurality of other information processing devices, and the plurality of other information processing devices respectively transmit the transmitted connection state information. The connection reproduction step is characterized in that one of a plurality of other information processing apparatuses storing the connection state information reproduces the connection with the computer. As a result, the number of information processing apparatuses that can take over the connection process with the computer increases, and the reliability of the system can be improved.

  The connection state information includes information for specifying a communication connection state with a computer and information handled by a process operating at the time of communication connection.

  In addition, the connection reproduction step may, for example, check the connection status with the computer based on the stored connection status information when another information processing device detects that a specific information processing device has failed. It is characterized by being reproduced.

And the other form of this invention is:
A cluster system comprising a plurality of information processing devices capable of providing the same information service to a predetermined computer connected via a network,
Connection state information for transmitting a connection state information, which is information necessary for a specific information processing apparatus in communication connection with the computer to reproduce the connection state with the computer, to the other information processing apparatus A transmission means,
Another information processing device receives connection state information transmitted from the specific information processing device and stores the connection state information receiving means, and connection state information stored according to the state of the specific information processing device. And a connection reproduction means for reproducing the connection state with the computer based on the above.

Furthermore, another aspect of the present invention is:
An information processing apparatus constituting a cluster system including a plurality of information processing apparatuses capable of providing the same information service to a predetermined computer connected via a network,
Connection state information transmitting means for transmitting connection state information, which is information necessary for reproducing the connection state with the computer, to another information processing device during communication connection with the computer;
A connection state information receiving unit that receives and stores connection state information transmitted from a connection state information transmission unit equipped in another information processing apparatus that is in communication connection with the computer when the computer is not in communication connection; Connection reproduction means for reproducing the connection state with the computer based on the connection state information stored in accordance with the state of the other information processing apparatus in communication connection with the computer;
It is characterized by having.

  Then, the connection state information transmitting means is a timing at which transmission / reception processing with the computer is normally executed, for example, timing at which an ACK signal is transmitted / received to / from the computer, particularly timing at which the ACK signal is transmitted to the computer. Thus, the connection state information is transmitted to another information processing apparatus.

  Further, the connection state information transmitting means transmits the connection state information to a plurality of other information processing apparatuses. The connection state information includes information for specifying a connection state with a computer and information handled by a process operating at the time of connection.

  The connection reproduction means monitors the status of another information processing apparatus that is in communication connection with the computer and detects that a failure has occurred in the information processing apparatus, based on the stored connection status information. It is characterized by reproducing the connection state with the computer.

Furthermore, the program which is the other form of this invention is:
In an information processing apparatus constituting a cluster system including a plurality of information processing apparatuses capable of providing the same information service to a predetermined computer connected via a network,
Connection state information transmitting means for transmitting connection state information, which is information necessary for reproducing the connection state with the computer, to another information processing device during communication connection with the computer;
A connection state information receiving unit that receives and stores connection state information transmitted from a connection state information transmission unit equipped in another information processing apparatus that is in communication connection with the computer when the computer is not in communication connection; Connection reproduction means for reproducing the connection state with the computer based on the connection state information stored in accordance with the state of the other information processing apparatus in communication connection with the computer;
It is characterized by realizing.

  Even the invention of the system, information processing apparatus, and program having the above-described configuration operates in the same manner as the above-described failover method, and thus the above-described object of the present invention can be achieved.

  Since the present invention is configured and functions as described above, according to this, in the cluster system, it is possible to quickly switch an information processing apparatus that provides a service to a client computer, and to stop providing the service. Therefore, the reliability of the system can be improved and the convenience of the user can be improved.

  In the present invention, in a cluster system including a plurality of information processing devices connected to a client terminal that receives service provision, another information processing device can be used while maintaining the connection state of the information processing device in communication with the client terminal. It is characterized in that it can be quickly switched to. Hereinafter, in the embodiment, a detailed configuration and operation will be described by taking as an example a cluster system that provides a network storage service to a client terminal. However, the failover function, which is a feature of the present invention, may be used in a cluster system that provides any information service, for example, may be used in a system that provides a Web service.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a cluster system, and FIG. 2 is a functional block diagram showing a configuration of a node among them. FIG. 3 is a diagram illustrating an example of a data structure of connection state information. FIG. 4 is a sequence diagram showing the failover operation in the cluster system, and FIGS. 5 to 6 are flowcharts showing the node operations. 7 to 9 are explanatory diagrams showing the operation of the cluster system.

[Constitution]
FIG. 1 shows the overall configuration of the cluster system in this embodiment. As shown in this figure, the cluster system in this embodiment includes a storage device 4 and a plurality of nodes 1, 2, 3 (information processing devices) connected to the storage device 4 via a SAN 40 (storage area network). And. A client terminal 5 (computer) is connected to each of the nodes 1, 2, 3 via a network, and a data sharing service for the storage apparatus 4, that is, a storage service is provided to the client terminal 5. A cluster system is configured. Note that it is sufficient that at least two nodes 1, 2, and 3 constituting the cluster system are provided, and the number of installed nodes is arbitrary.

  Each of the nodes 1, 2, and 3 is configured by a server computer and functions as a relay point that connects the client terminal 5 and the storage apparatus 4. That is, one of the nodes 1, 2, and 3 has a function of providing a file sharing service to the storage apparatus 4 by connecting one of them to the client terminal 5 using the CIFS protocol based on TCP / IP. Then, when a failure occurs in the connected node and the connection with the client terminal 5 cannot be maintained, the other node has a failover function that takes over the connection with the client terminal 5 and continuously provides the service. . Hereinafter, the configuration of the nodes 1, 2, and 3 will be described. Since all have the same configuration, the node indicated by reference numeral 1 will be described as an example.

  As shown in FIG. 2, the node 1 is equipped with a CPU 1A that is an arithmetic device and a memory 1B that is a storage device. The CPU 1A is configured with a communication processing unit 11, a connection state copy processing unit 12, and a connection reproduction processing unit 13 by incorporating a program. In addition, a connection state information storage unit 14 in which connection state information is stored is formed in the memory 1B. The details will be described below.

  The communication processing unit 11 has a function of connecting to the client terminal 5 by using the CIFS protocol using the TCP connection, and allows the storage apparatus 4 to be shared. Along with this, the client terminal 5 is also equipped with a function of connecting to the nodes 1, 2, and 3 using the CIFS protocol. The communication device 11 functions to connect to the storage device 4 and further functions to connect to other nodes 2 and 3.

  As described above, the connection state copy processing unit 12 (connection state information duplicating means) extracts the connection state information indicating the connection state with the client terminal 5 in communication connection by the CIFS protocol, and transmits it to other nodes. It has a function. Specifically, as shown in FIG. 3, the connection status information includes connection information (for example, transmission / reception IP address, port number, TCP sequence number, return ACK number, etc.) for specifying the communication connection status with the client terminal 5. , Information including information (for example, data (context) held by the process, program counter, etc.) handled by the process operating at the time of communication connection. The connection state information is information necessary for reproducing the connection state between the node 1 and the client terminal 5 between the other nodes 2 and 3 and the client terminal 5. That is, as will be described later, the other nodes 2 and 3 can reproduce the connection state with the node 1 communicating with the client terminal 5 by obtaining the connection state information and using it.

  Then, the connection status copy processing unit 12 uses the TCP / IP protocol in particular when the transmission / reception process of the client terminal 5 in communication is performed normally, that is, when the data of the client terminal 5 is transmitted / received. Then, at the timing when the “ACK signal” which is a positive reply sent from the data transmission destination to the transmission source is transmitted / received, it operates to transmit the connection state information to the other nodes 2 and 3. Specifically, in this embodiment, the client terminal 5 transmits data to the node 1 and returns an ACL signal to notify the client terminal 5 that the node 1 has received the data normally. When this ACK signal is returned, the node 1 transmits connection state information to the other nodes 2 and 3. At this time, the connection state copy processing unit 12 of the node 1 transmits the connection state information directly to the memories (not shown) of the other nodes 2 and 3 by RDMA (Remote Direct Memory Access) technology.

  Further, when the node is not in communication connection with the client terminal 5, the connection state copy processing unit 12 receives the above-described connection state information transmitted from another node, and the connection state information storage unit of the memory 1B 14 has a function (connection state information receiving means) for storing. In other words, in the present embodiment, the connection state copy processing unit equipped in the other nodes 2 and 3 is the node 1 transmitted from the connection state copy processing unit 12 of the node 1 connected to the client terminal 5. The connection state information is received and stored in the memory.

  The connection reproduction processing unit 13 (connection reproduction means) mainly functions in a node that is not connected to the client terminal 5. Therefore, here, the description will be made assuming that the node 2 of the reference numeral 2 is equipped. This connection reproduction processing unit first monitors the state of other nodes (here, nodes 1 and 3) via the communication processing unit. In particular, it monitors whether a failure has occurred in the node 1 communicating with the client terminal 5. When detecting that a failure has occurred in the node 1, the connection state information stored in the connection state information storage unit (see reference numeral 14) of its own memory is read out, and the client is based on the connection state information. The connection state with the terminal 5 is reproduced, and the node 2 operates to restore the service provision to the client terminal 5. That is, the state when the node of the reference numeral 1 is connected to the client terminal 5 is reproduced and inherited by the node of the reference numeral 2 as it is. Such takeover processing can be realized by using connection information and process information as described above.

[Operation]
Next, the operation of the system configured as described above will be described with reference to FIGS. 4 is a sequence diagram illustrating the operation of the entire system, FIG. 5 is a flowchart illustrating the operation of the node denoted by reference numeral 1, and FIG. 6 is a flowchart illustrating the operation of the node denoted by reference numeral 2. 7 to 9 are explanatory diagrams showing a connection state and a data flow.

  First, a communication connection is established between the client terminal 5 and the node 1 denoted by reference numeral 1 (steps S1 and S2 in FIG. 4, (1) in FIG. 7), and the node 1 starts providing the CIFS service (step in FIG. 5). S21), providing the CIFS service to the client terminal 5 (step S22 in FIG. 5). Thereby, the client terminal 5 can use the storage service provided by the node 1. That is, the storage apparatus 4 can be accessed, and file recording / reproduction can be performed on the storage apparatus 4.

  Then, there is data (A) transmission from the client terminal 5 (step S3 in FIG. 4), and when this is completely received by the node 1, an ACK signal indicating reception confirmation is returned to the client terminal 5 (step in FIG. 4). S4, Yes in step S23 of FIG. 5, (2) of FIG. Then, the node 1 extracts connection state information indicating the connection state with the client terminal 5 at the timing of this ACK return (step S24 in FIG. 5), and transmits it to the other nodes 2 and 3 (in FIG. 4). Step S5, step S25 in FIG. 5, (3) in FIG. 7, connection state information duplicating step).

  On the other hand, the other nodes 2 and 3 receive the connection state information transmitted from the node 1 (step S31 in FIG. 6) and store it in the connection state information storage unit in the memory (FIG. 4). Step S6, step S32 in FIG. 6, connection state information duplication step). After that, until the CIFS service provision ends (No in step S26 in FIG. 5 and no in step S33 in FIG. 6), the node 1 transmits connection status information every time an ACK signal is transmitted to the client terminal 5, as described above. Are transmitted to the other nodes 2 and 3, and in response to this, the nodes 2 and 3 receive the transmitted connection state information and store the latest one.

  Next, consider the case where a failure occurs in node 1. Here, as shown in FIG. 4, the data (B) is transmitted from the client terminal 5 to the node 1 (step S7 in FIG. 4), and before the node 1 completely receives it, the node 1 has a fault. It is assumed that the error occurred (step S8 in FIG. 4, yes in step S33 in FIG. 6, (4) in FIG. 8). Then, the other nodes 2 and 3 detect the failure of the monitored node 1 (step S9 in FIG. 4), and it is decided to take over the processing of the node 1 by the preset exchange between the nodes 2 and 3 The node denoted by reference numeral 2 reads the connection state information received from the node 1 stored in its own memory, and reproduces the connection with the client terminal 5 based on the read connection state information. Thereby, the node 2 recovers the CIFS service for the client terminal 5 (step S10 in FIG. 4 and step S35 in FIG. 6), the connection of the client terminal 5 to the node 1 is taken over by the node 2, and the node 2 Connection with the client terminal 5 is established (steps S11 and S12 in FIG. 4, (5) in FIG. 8 (see arrow Y1), connection reproduction step). When the node 2 detects the failure of the node 1, since the connection state information for taking over the connection has already been stored, the takeover process can be executed quickly.

  Thereafter, the CIFS service is provided from the node 2 to the client terminal 5 (step S36 in FIG. 6). Then, the client terminal 5 transmits the data (B) before the failure occurs in the node 1 (see step S7 in FIG. 4), but has not obtained the ACK signal that is the reception confirmation signal for this, so the data (B) is retransmitted (step S13 in FIG. 4). Then, since the node 2 is currently connected, data (B) is transmitted to the node 2. Therefore, since the process before the failure of the node 1 is taken over by the node 2, the process can be reliably continued. When the node 2 completely receives the data (B) from the client terminal 5, the node 2 transmits an ACK that is a reception confirmation signal to the client terminal 5 (step S14 in FIG. 4, (6) in FIG. 9). At the same time, the node 2 transmits connection state information indicating the connection state with the client terminal 5 at this time to the other nodes 1 and 3 (step S15 in FIG. 4 and FIG. 9). (7)). However, when the node 1 remains in a failure occurrence state, it is not transmitted to the node 1.

  As described above, according to the present invention, first, since the information indicating the connection state of the node 1 that is always communicating with the client terminal 5 is copied to the other node 2, Thus, it is possible to quickly take over the connection state, improve the reliability, and improve the convenience for the user. In particular, by setting the timing of copying the connection status information as the transmission timing of the ACK signal, it is possible to take over the connection to another node in a state in which the data communicated with the client terminal is guaranteed, and further reliability Can be improved. This eliminates the need to set a special checkpoint in advance as the timing for copying connection state information to a node application, etc., reducing application creation costs and reducing the processing burden on the node. Become.

  In the above description, the timing of copying the connection state information has been described as an example of the transmission of the ACK signal. However, the communication data between the client terminal 5 and the node 1 in communication connection is guaranteed. For example, the connection state information may be copied at any timing. For example, the connection state information may be copied to another node at a data guarantee timing such that data whose disk I / O has not been completed is copied to another node.

  In the above description, the nodes 1, 2 and 3 are server computers. However, any device may be used as long as the information processing device has the above-described configuration. For example, a router may be used.

  Furthermore, in the above description, a cluster system that provides a storage service is illustrated as a system equipped with nodes, but the present invention may be applied to other systems. For example, the nodes may be configured by a plurality of web servers that open the same website and provide web services.

  The failover method of the present invention can be applied to uses such as failover of a cluster system that provides a network storage service and failover of a system that provides a web service, and has industrial applicability.

It is a block diagram which shows the structure of a cluster system. It is a functional block diagram which shows the structure of a node. It is a figure which shows an example of the data structure of connection state information. It is a sequence diagram which shows the operation | movement of failover in a cluster system. It is a flowchart which shows operation | movement of a node. It is a flowchart which shows operation | movement of a node. It is explanatory drawing which shows the operation | movement at the time of failover of a cluster system. It is explanatory drawing which shows the operation | movement at the time of failover of a cluster system. It is explanatory drawing which shows the operation | movement at the time of failover of a cluster system.

Explanation of symbols

1, 2, 3 Node 4 Storage device 5 Client terminal 11 Communication processing unit 12 Connection state copy processing unit 13 Connection reproduction processing unit 14 Connection state information storage unit

Claims (16)

A failover method in a cluster system comprising a plurality of information processing devices capable of providing the same information service to a predetermined computer connected via a network,
A specific information processing apparatus in communication connection with the computer transmits connection state information, which is information necessary for reproducing the connection state with the computer, to the other information processing apparatus. The connection state information duplication step in which the other information processing apparatus receives and stores the transmitted connection state information,
The other information processing apparatus reproduces the connection state with the computer based on the stored connection state information according to the state of the specific information processing apparatus,
A failover method characterized by comprising: The connection state information duplication step transmits the connection state information to the other information processing device at a timing when a predetermined transmission / reception process between the specific information processing device and the computer is normally executed.
The failover method according to claim 1, wherein: The connection state information duplication step transmits the connection state information to the other information processing device at a timing at which an ACK signal is transmitted and received between the specific information processing device and the computer.
The failover method according to claim 2, wherein: The connection state information duplication step transmits the connection state information to the other information processing device at a timing when the specific information processing device transmits an ACK signal to the computer.
The failover method according to claim 3, wherein: In the connection state information replication step, the specific information processing apparatus transmits the connection state information to a plurality of other information processing apparatuses, and the plurality of other information processing apparatuses transmit the transmitted connection state information. Each received and memorized,
In the connection reproduction step, one of the plurality of other information processing apparatuses storing the connection state information reproduces the connection with the computer.
A failover method characterized by that. The connection state information includes information for specifying a communication connection state with the computer, and information handled by a process operating at the time of communication connection.
The failover method according to claim 1, 2, 3, 4 or 5. In the connection reproduction step, when the other information processing apparatus detects that a failure has occurred in the specific information processing apparatus, a connection state with the computer is determined based on the stored connection state information. Reproduce,
The failover method according to claim 1, 2, 3, 4, 5, or 6. A cluster system comprising a plurality of information processing devices capable of providing the same information service to a predetermined computer connected via a network,
A specific information processing apparatus in communication connection with the computer transmits connection state information, which is information necessary for reproducing the connection state with the computer, to the other information processing apparatus. Connection state information transmitting means for
The other information processing apparatus receives and stores the connection state information transmitted from the specific information processing apparatus, and stores the connection state information according to the state of the specific information processing apparatus. Connection reproduction means for reproducing the connection state with the computer based on the connection state information,
A cluster system characterized by that. An information processing apparatus constituting a cluster system including a plurality of information processing apparatuses capable of providing the same information service to a predetermined computer connected via a network,
A connection state information transmitting means for transmitting connection state information, which is information necessary for reproducing a connection state with the computer, to another information processing apparatus during communication connection with the computer;
Connection state information for receiving and storing the connection state information transmitted from the connection state information transmitting means provided in another information processing apparatus that is in communication connection with the computer when not in communication connection with the computer Receiving means; and connection reproduction means for reproducing the connection state with the computer based on the connection state information stored according to the state of another information processing apparatus in communication connection with the computer;
An information processing apparatus comprising: The connection state information transmitting means transmits the connection state information to another information processing apparatus at a timing at which transmission / reception processing with the computer is normally executed,
The information processing apparatus according to claim 9. The connection state information transmitting means transmits the connection state information to another information processing device at a timing at which an ACK signal is transmitted to and received from the computer.
The information processing apparatus according to claim 10. The connection state information transmitting means transmits the connection state information to another information processing apparatus at a timing of transmitting an ACK signal to the computer.
The information processing apparatus according to claim 11. The connection state information transmitting means transmits the connection state information to a plurality of other information processing devices.
The information processing apparatus according to claim 9, 10, 11, or 12. The connection state information includes information for specifying a connection state with the computer, and information handled by a process operating at the time of connection.
The information processing apparatus according to claim 9, 10, 11, 12, or 13. The connection reproduction means monitors the state of another information processing apparatus in communication connection with the computer and detects that a failure has occurred in the information processing apparatus, based on the stored connection state information. To reproduce the connection status with the computer,
The information processing apparatus according to claim 9, 10, 11, 12, 13, or 14. In an information processing apparatus constituting a cluster system including a plurality of information processing apparatuses capable of providing the same information service to a predetermined computer connected via a network,
A connection state information transmitting means for transmitting connection state information, which is information necessary for reproducing a connection state with the computer, to another information processing apparatus during communication connection with the computer;
Connection state information for receiving and storing the connection state information transmitted from the connection state information transmitting means provided in another information processing apparatus that is in communication connection with the computer when not in communication connection with the computer Receiving means; and connection reproduction means for reproducing the connection state with the computer based on the connection state information stored according to the state of another information processing apparatus in communication connection with the computer;
A program to realize

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